在 VB.NET 中将字符串转换为 XML 节点
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Converting string to XML node in VB.NET
提问by Sandeep Thomas
I've an XML string in database column like this
我在数据库列中有一个像这样的 XML 字符串
<trueFalseQuestion id="585" status="correct" maxPoints="10"
maxAttempts="1"
awardedPoints="10"
usedAttempts="1"
xmlns="http://www.ispringsolutions.com/ispring/quizbuilder/quizresults">
<direction>You have NO control over how you treat customers.</direction>
<answers correctAnswerIndex="1" userAnswerIndex="1">
<answer>True</answer>
<answer>False</answer>
</answers>
</trueFalseQuestion>
But I need to do XML operations on this string like select its name, attributes values,inner text etc. How can I make this possible from this string
但是我需要对这个字符串做 XML 操作，比如选择它的名称、属性值、内部文本等。我怎样才能从这个字符串中做到这一点
EDIT
编辑
Im sharing the code snippet I tried, but not working
我分享了我试过的代码片段，但没有用
Dim myXML As String
Dim gDt As New DataTable
gDt.Columns.Add("id")
gDt.Columns.Add("questionid")
gDt.Columns.Add("serial")
gDt.Columns.Add("direction")
Dim dr As DataRow
myXML ='<my above shared XML>'
Dim xmlDoc As New XmlDocument
xmlDoc.LoadXml(myXML)
dr = gDt.NewRow
dr("serial") = 1
dr("id") = xmlDoc.Attributes("id").Value
dr("direction") = xmlDoc("direction").InnerText
gDt.Rows.Add(dr)
But thats not working at all as I wish
但这根本不像我希望的那样工作
回答by Steven Doggart
There are many ways to parse XML in .NET, such as using one of the serialization classes or the XmlReaderclass, but the two most popular options would be to parse it with either XElementor XmlDocument. For instance:
在 .NET 中有很多解析 XML 的方法，例如使用序列化类或XmlReader类之一，但两个最流行的选择是使用XElement或解析它XmlDocument。例如：
Dim input As String = "<trueFalseQuestion id=""585"" status=""correct"" maxPoints=""10"" maxAttempts=""1"" awardedPoints=""10"" usedAttempts=""1"" xmlns=""http://www.ispringsolutions.com/ispring/quizbuilder/quizresults""><direction>You have NO control over how you treat customers.</direction><answers correctAnswerIndex=""1"" userAnswerIndex=""1""><answer>True</answer><answer>False</answer></answers></trueFalseQuestion>"
Dim element As XElement = XElement.Parse(input)
Dim id As String = element.@id
Or:
或者：
Dim input As String = "<trueFalseQuestion id=""585"" status=""correct"" maxPoints=""10"" maxAttempts=""1"" awardedPoints=""10"" usedAttempts=""1"" xmlns=""http://www.ispringsolutions.com/ispring/quizbuilder/quizresults""><direction>You have NO control over how you treat customers.</direction><answers correctAnswerIndex=""1"" userAnswerIndex=""1""><answer>True</answer><answer>False</answer></answers></trueFalseQuestion>"
Dim doc As New XmlDocument()
doc.LoadXml(input)
Dim nsmgr As New XmlNamespaceManager(doc.NameTable)
nsmgr.AddNamespace("q", "http://www.ispringsolutions.com/ispring/quizbuilder/quizresults")
Dim id As String = doc.SelectSingleNode("/q:trueFalseQuestion/@id", nsmgr).InnerText
Based on your updated question, it looks like the trouble you were having is that you weren't properly specifying the namespace. If you use XElement, it's much more forgiving (i.e. loose), but when you use XPath to select nodes in an XmlDocument, you need to specify every namespace, even when it's the default namespace on the top-level element of the document.
根据您更新的问题，您遇到的问题似乎是您没有正确指定命名空间。如果您使用XElement，它会更加宽容（即松散），但是当您使用 XPath 在 中选择节点时XmlDocument，您需要指定每个名称空间，即使它是文档顶级元素上的默认名称空间。
